Film feeding mechanism



July 5 1938. P. LIRA mm FEEDING MECHANISM Filed Dec. 30, 1955 4Sheets$heet l July 5, 1938. P. LIRA FILM FEEDING MECHANISM Filed Dec.50, 1935 4 SheetsSheet 2 5// t IIIIIIII'IIIIIIIIIIIIIIIIIII July 5,1938. |RA 2,122,946

FILM FEEDING MECHANISM Filed Dec. 50, 1935 4 Sheets-Sheet 3 July 5,1938.

P. LIRA FILM FEEDING MECHANISM Filed Dec. 50, 1935 4 Sheets-Sheet 4Patented July 5, 1938 UNITED STATES PATENT OFFICE 4 Claims.

My invention" relates to improvements in the cinematographic mechanismdescribed in .my Patent No. 1,992,706 granted February 26, 1935 and inmy Patent No. 2,021,560 issued November Said improvements are mainlydesigned for cine-projectors and refers to the following points:

(a) The connection between the rocker-shaft and the reciprocatingfilm-carrier or oscillator;

(b) The use of compressed air actioned pistons instead of springs toforce a continuous contact between the oscillator and the rockershaft;

(c) The use of reciprocating pistons actioned 5 by compressed air forcounterbalancing the reciprocating film-carrier movement;

(41) A device for increasing the adherence between the driving-pulleyand the film;

(e) A device to keep the film fiat when passing through the field of thelens;

(1) The elimination of the play in the spur gears connecting thecam-shaft with the drivingpulley shaft; and

(g) The differential friction gearing between :5 the cam-shaft and thedriving pulley shaft, or

differential corrector.

The object of my invention is to secure a more silent, efficient andaccurate running of the whole mechanism.

:30 I reach these objects by means of the mechanisms shown in theaccompanying drawings,

wherein:

Figure 1 is a general side view of the central parts of thecine-projector mechanism, without indication of the means for thetransmission of the movement.

Figures 2 and 3 show the rocker-arm and its connection to thereciprocating film-carrier, as follows: Figure 2 is a plan view andFigure 3 is a 10 front elevation.

Figure 4 is a section on the line IV-IV of Figure 1, showing thecompressed air actioned pistons and their connection with thereciproeating film-carrier.

4.; Figures 5 and 6 show the reciprocating pistons actioned bycompressed air for counterbalancing the reciprocating film-carriermovement, as follows: Figure 5 is a side view and Figure 6 is a sectionon the line VIVI of Figure 5.

120 Figures '7 and 8 show a device for increasing the adherence betweenthe driving pulley and the film, as follows: Figure '7 is a side viewand Figure 8 is a rear elevation in which the endless strip has beenomitted for the sake of clear- 55 ness.

Figures 9 and 10 show a device for keeping the film fiat when passingthrough the field of the lens, as follows: Figure 9 is a front elevationand Figure 10 is a section on the line XX of Figure 9.

Figure 11 shows diagrammatically the transmission of the movement fromthe cam-shaft to the driving pulley shaft of the mechanism shown inFigure 1.

Figures 12 and 13 show a device to eliminate 1 the play in the spurgears, as follows: Figure 12 is a section on the line XII-XII of Figure13 and view of the mechanisms behind this section, and Figure 13 is asection on the line XIII- XIII of Figure 12. 18

Figures 14 and 15 show a new device for th differential friction gearingbetween the camshaft and the driving pulley shaft, which I name"differential corrector, as follows: Figure 14 is a section on the lineXLV -XIV of Figure 15, and Figure 15 is a section on the line XV-XV ofFigure 14 and view of the mechanisms behind this section.

The same letters and numbers denote the same parts throughout thedrawings.

General description of the mechanism In Figure 1 a1 is the film comingfrom the unwinding reel at a constant tension as explained in my PatentNo. 1,992,706.

b is a. tension free roller supported by an arm free to pivot on fixedshaft 0, regulating the tension of the film by means of a spring d.

e, e1 are free rollers with fixed shafts, which I will name oscillatorincoming roller and oscillator outcoming roller respectively.

I, ii are the free rollers of the reciprocating film-carrier (oroscillator); these rollers are connected by means of rigid oscillatingframes g and g1 to the fixed shafts of the roll- 40 ers e and c1respectively.

or are two parallel rods connecting the frames g and g1.

71. is a rocker-shaft provided with a rockerarm in connected to theoscillating frame 9 by means of the intermediary pushing-rod i.Rocker-shaft is also in connection with a cam mounted on a cam-shaft notshown in Figure 1 for the sake of clearness.

7' are movable pistons free to slide into fixed hollow cylinders isconnected to a compressed air tank (not shown in the drawings).

1 is the mounting of the lens. provided with an extension 11 whichsupports the part 0 designed for keeping the film flat when passingthrough the field of the lens.

111. is a support for the mounting l of the lens; said support m can beshifted upwards or downwards, sliding on fixed guides 12. min order tocenter the projected picture.

p is a pulley fixed on a shaft D1 whose rotation produces a continuousand uniform driving of the film simply by adherence; I name it drivingpulley".

si, s: are free rollers supported by a mounting-t which pivot on fixedshaft u.

sa is a free roller supported by a mounting t1 which pivots on the sameshaft 1!. of mounting t. r is an endless strip passing over the rollers81, 8:, s1.

v is a spring continuously tending to separate mountings t and t1,whereby the endless strip r is kept in tension.

10 is a catch which serves to keep the mounting t in a suitable positionfor pressing the endless strip 1' against the driving pulley 1) withoutpressing rollers .91 and s: against same pulley.

q is a free roller on a fixed shaft; and

a: is the film going to the rewinding reel at a constant tension asexplained in my Patent'No.

There must be a general support for the mechanism, which I will nameprojector frame part". For the sake of clearness all the shafts inFigure 1 which are directly supported by said projector frame part arehatched.

The means for the transmission of the movement from the camshaft to thedriving-pulley shaft are shown in Figure 11, as follows:

I! is the cam-shaft, which is supposed to be the power-shaft also.

Camshaft 29 is geared to shaft 3| by means of intermediate shaft 30. Onshaft 3| is mou'nted a flat friction disc 32.

Shaft 35 bears flat friction disc 36 parallel to disc 32 and frictiongeared to it by means of the intermediate friction wheel 33 mounted on atransversal shaft 34.

Shaft 35 is also geared to the driving pulley shaft 121 by means of theintermediary shaft 31.

The assembly of shafts 3|, 34 and 35 forms a device which I namedifferential corrector and is described hereinafter in detail. Theobject of this device is to change at will the gear ratio between thecamshaft 29- and the driving-pulley shaft p1, so that the running of thefilm may be regulated according to the small possible difi'erences inthe distance between the centers of successive frames or pictures insaid film, due to the expansion or to the shrinking of Celluloid.

It is worth being mentioned that cam-shaft 29 is geared also to therewinding reel dragging mechanism, as explained in my Patent No.1,992,706.

Working of the cinematographic mechanism. The film comes from theunwinding reel at 0.1 and runs successively over the tension roller b,the oscillator incoming roller e, the oscillator upper roller f, thepart 0, the oscillator lower roller 11, the outcoming roller e1, thedriving pulley p, and the free roller q, going finally at oz to therewinding reel.

When the cam-shaft 29 works, its movement is transmitted to the drivingpulley p and to the rewinding reel dragging mechanism through thegearing, as formerly described.

As a result of this the film is set in tension all along its way fromthe unwinding reel to the rewinding one, and a continuous and uniformrunning of the film follows owing to the adherence between the film andthe driving pulley, as explained in detail in my Patent No. 1,992,706.

At the same time the action of the cam on the rocker-shaft h produces areciprocating movement of the oscillator rollers f and f1, whereby themovement of the film when passing through the field of the lens iscomposed .of successive stops and runs, owing to the composition of theuniform velocity of the film with the reciprocating movement of theoscillator, as explained in detail in my Patent No. 1,992,706.

The present application refers to improvements in several details of themechanism, as formerly stated.

Improvements in the connection between the rocker shaft and thereciprocating film carrier. The direct contact between the rocker-armand a bar fixed on the reciprocating film-carrier, as shown in my PatentNo. 1,992,706, gives occasion for a friction between said parts andcauses a secondary reciprocating movement of the film carrier on accountof the inevitable small play of it in its guides of movement. Saidsecondary reciprocating movement affects the uniform tension of the filmand, consequently, the good running of the mechanism.

The object of the device herein described is to prevent said difilculty.

Reference is made to Figures 1, 2 and 3.

i is a pushing rod interposed between the oscillating frame 9 and therocker-arm hr. Pushing rod iis designed with a semi-cylindrical shape atboth ends; and the same shape, in hollow, is provided on its supports;whereby pushing rod 1, which is always under compression, works as aconnecting rod between rocker-arm h1 and oscillating frame 9.

Pushing rod 1 is connected to the rocker-arm hr by means of theintermediary supporting part I, fastened to the rocker-arm m by means ofa screw 2.

An elongated boring 3 in part i allows to slide it along the rocker-armin when screw 2 is loosened.

By means of this device the amplitude of the reciprocating movement canbe increased or decreased simply by setting part I more or less apart ofthe rocker-shaft h.

When the proper setting of part I in order to equalize the velocity ofthe reciprocating filmcarrier upwards stroke with the uniform downwardsvelocity of the film is obtained, and therefore absolute stops and runsof the film are secured, screw 2 is fastened and part i is kept in theright position.

The intercalation of pushing rod 1' between the rocker-arm h1 and theoscillating frame 9 prevents the troublesome friction above referred.

Compressed air pistons.In my Patents No. 1,992,706, and No. 2,021,560,springs are used to force a continuous contact between the oscillatorand the rocker-arm. Experience has shown that such springs, when movingat high speed and acceleration, lose a considerable portion of theirstrength and, moreover, they set into vibrations which are troublesome.

The object of the device herein described is to avoid said difliculty.

Reference is made to Figures 1 and 4.

Cylinders k are mounted (or bored) on part 4 fixed to the projectorframe part 5.

6 is a pipe connecting the inside chamber of cylinders k to a compressedair tank.

9' are light hollow pistons free to slide into cyl- 1| inders It; saidpistons are connected to the oscillating frame or by means of pushingrods 1.

The action of compressed air on pistons 1 produces a continuous pressingof them, through rods 1, on the oscillating frame g1 and, on account ofconnecting rods :72, forces a continuous contact between the upperoscillating frame a and the rocker-arm h1- Vibrations are completelyprevented. The force exerted by pistons i on frame or is the same at anyspeed or acceleration and can be adjusted to the right amount by meansof the pressure on the compressed air tank.

Consumption of compressed air is small and due only to leakage betweenthe pistons and cylinders,

or through the connections of piping,

counterbalance of the reciprocating film-carrier movement.1n my PatentNo. 2,021,560 a device is shown for preventing strong reactions on thebearings of the rocker shaft and the camshaft produced by the oscillatorreciprocating movement on account of inertia.

Said device consists substantially in-the provision of reciprocatingcounterweights arranged at both sides of the reciprocating film-carrier,and of a cam and a rocker-shaft for reciprocating said counterweights.The reciprocating movement and the mass of the counterweights is sosettled that the inertial reactions produced by them are always equal invalue but opposite in direction to the inertial reactions produced bythe reciprocating film-carrier. I

The whole device, as shown in detail in my Patent No. 2,021,560,includes springs to force a continuous contact of the reciprocatingcounterweights against their respective rocker-arms, giving occasion forsimilar troubles as those above stated when referring to the springsacting on the reciprocating film-carrier.

The object of the device herein described is to avoid said troubles.

Reference is made to Figures 5 and 6.

Cylinders 9 are mounted (or bored) on part 8 fixed to the projectorframe part 5.

I0 is a pipe connecting the inside chamber of cylinders 9 to acompressed air tank.

II are pistons free to slide into cylinders 9; said pistons areconnected to rocker-arms ll by means of pushing rods i2 and intermediaryparts I3 which are similar to parts i and I above described whenreferring to the connection between the reciprocating film-carrier andits rocker-arm.

Rocker-arms H are mounted on a hollow rocker-shaft l5 actioned by a cam(not shown in the drawings).

Cylinders 9 are arranged at both sides of the oscillator, although notshown in Figure 1 for the sake of clearness; and the rocker shaft hwhich imparts the reciprocatingmovement to the film-carrier, passesthrough the hollow of rockershaft IS.

The whole assembly of the rocker-shafts, cams and cam-shaft is the sameas described in my Patent No. 2,021,560.

settled in order to produce the same inertial re actions astheoscillator at the same velocities.

Owing to the former dispositions, the inertial reactions of theoscillator and of the reciprocating pistons are always counter-balanced.

Summing up the above, it may be seen that the device herein describeddiffers from the one described in my Patent No. 2,021,560 only in twopoints, namely:

(a) The use of compressed air actioned pistons instead of springs,

(b) The use of the weight of the same pistons in substitution of thereciprocating counterweights.

This new device is more simple and completely vibrationless.

Device for increasing the adherence between the driving pulley and thefilm.--Experience has shown that owing to vibrations the adherencebetween the film and the driving pulley may be momentarily weakened; theobject of the device herein described is to prevent said difficultywithout damaging the film.

Reference is made to Figures 1, '7 and 8.

s1, S2 are free rollers supported by a mounting t which can pivot on ashaft u fixed to the projector frame part 5.

s: is a free roller supported by a mounting t1 which can pivot on thesame shaft u as mounting t.

r is an endless strip passing over rollers 81, sz and s3. 7

v is a spring continuously tending to separate mountings t and t1,whereby the endless strip 1' is kept in tension. I

w is a catch free to pivot on shaft l6 fixed to the projector frame part5; said catch serves for keeping mounting t in position when the deviceis at work.

Catch w is actioned by a spring I! and is provided with a handle Hi.

The working of the device is as follows:

When the cine-projector is at rest, catch w must be disengaged and theassembly of mountings t, t1 kept apart of the driving pulley p (as shownin Figure '7).

For starting a projection a film must be previously arranged through thewhole mechanism as shown in Figure 1, and after this has been done,mounting t is engaged on catch w.

When so, the endless strip 1' is pressed against the film, andconsequently increases the pressure of said-film against the drivingpulley p,

whereby the force of adherence between the film and the driving pulleyis increased.

A substantial feature of the device is that" catch w is so settled thatonly the strip r is in contact with the film, whilst rollers .91, and 82are kept apart of the driving pulley 1), whereby only a uniformdistributed pressure is exerted on the film through the strip 1', andthe damage of the film due to strong concentrated pressures, as thoseexerted by the direct action of pressing rollers, is avoided.

Device to keep the film flat when passing through the field of theZena-The object of this device is to keep the frames of the filmperfectly fiat when passing through the field of the lens in order tosecure a neat projected picture.

A substantial feature of the device is to allow any transversaldisplacement of the film.

Reference is made to Figures 1, 9 and 10.

Part 0 has an opening I9 of the same size as the frames of the film.Protruding bands 20 are provided on part 0 at both sides of opening l9in order to prevent any injury to the central printed part of the film.

Blades 2| provided with handles 22 are mounted on shafts 23 at each sideof part 0. Springs 24 press slightly blades 2| against protruding bands28.

The film passes between bands 28 and blades 2| when passing in front ofopening l9 through the field of the lens, whereby the projected frame ofthe film is kept fiat owing to the pressure exerted by blades 2|.

Part is hung by means of wheels 25 to rail 26 fixed on the extension 11of the lens mounting 1; therefore part 0 is free to move laterally.

A wheel 21 arranged on the lower part of part 0 serves to keep said partparallel to the field of the lens.

Lateral flanges 28 on part 0 serve to keep the film centered with saidpart; but it must be remarked that said fianges 28 are not intended toguide the film, but, contrarily, they are provided in order to allow thefilm to move laterally the part 0 if its free running so requires.

Elimination of the play in the spur gears connecting the cam-shaft tothe driving pulley shaft-As it has been explained in my Patent No,1,992,706, if the constant tension devices acting over the unwinding andthe rewinding reels are properly set, the tension of the film before andafter passing over the driving pulley is nearly the same.

In practice not only noticeable differences continuously occur, butsometimes the tension of the film is greater before passing over thedriving pulley, and sometimes it is greater after passing over saidpulley.

When the first case occurs, the gearing connecting the camshaft to thedriving pulley shaft forces the latter to revolve, overcoming theresistance opposed by the film.

When the second case occurs, the gearing connecting the camshaft withthe driving pulley shaft exerts a braking action on the latter of them.

When a change from one to the other of the above explained cases occurs,the driving pulley shaft revolves freely during a short instant onaccount of the play between the teeth of the spur gears; and as aconsequence the velocity of the film suffers a momentary alteration, anda small displacement of the projected picture follows.

The object of the device herein described is to prevent said fault.

Reference is made to Figures 12 and 13.

Pi is the driving pulley shaft.

38 is a spur wheel fixed on shaft pl.

39 is a spur wheel identical to spur wheel 38 but free to revolve aroundshaft 171.

48 is a spring having one end fixed on shaft p1 and its other endapplied over crank 4| fixed on spur wheel 38.

43 is a screw fixed on gear 38 and passing through an elongated opening44 on wheel 39.

45 is a nut and lock-nut on screw 43.

42 is the spur wheel geared to spur wheels 38 and 39.

The mounting and working of the device is as follows:

Before mounting the gearing, the teeth of gears 38 and 39 are setcoincident and nut 45 is screwed, thus fastening the wheel 39 againstwheel 38 and preventing the rotation of wheel 39 under the action ofspring 40; after which the mounting is done in the same way as with anyspur gearing.

After mounting is done, nut 45 is loosened and locked on screw 43 asshown in Figure 13, whereby spur wheel 38 is free to revolve on shaftp1: and, under the action of spring 48, the teeth of spur wheel 42 areimprisoned between the teeth of spur wheels 38 and 39 whereby all playof the gearing is suppressed.

It may be criticized that the pressure between the teeth of the gears isincreased and that a complementary passive resistance is introduced inthe mechanism; but if an adequate lubrication is used, this fault is ofno account owing to the small amount of the power to be transmitted.

Furthermore, there is an alternative use of the device which permits toreduce the play of the gears to a minimum nevertheless avoiding theabove stated fault. In order to do this, nut 43 must be screwedfastening wheel 39 to wheel 38 after the play of the gearing has beenreduced to the wanted amount.

Although Figures 12 and 13 refer to the driving pulley shaft, it must beunderstood that the same device is used in all the spur gearing betweenthe cam-shaft and the driving pulley shaft.

Difierential corrector.The object of this mechanism is to allow smalland exact changes of the gear ratio between the cam-shaft 29 and thedriving pulley shaft 111.

Reference is made to Figures 14 and 15.

Shaft 3|, supported by the projector frame part 5, has a fiat frictiondisc thereon, and is supposed to be geared by means of spur wheel 48 tothe camshaft 29.

Shaft 35, supported by the projector frame part 5, has a flat frictiondisc 36 thereon, and is supposed to be geared by means of spur wheel 41to the driving pulley shaft 121.

The axes of shafts 3| and 35 are parallel but not coincident, on thecontrary it is substantial for the working of the mechanism that theyare set apart some distance 2.

An intermediary shaft 34 is screwed on the projector frame part at 49,so that it can be shifted along its axis by means of handle 48. Mountedon shaft 34 but free to revolve around it is a friction wheel 33.

Springs 50 acting over thrust collars 5| press fiat discs 32 and 36against friction wheel 33, whereby friction gearing is secured fromshaft 3| to shaft 35 through the intermediary wheel 33.

The working of the differential device is as follows:

When the mechanism is running and handle 48 is turned, the radius of thecircles in discs 32 and 35 which come in contact with the intermediaryfriction wheel 33 are both simultaneously increased or decreased; so,the gear ratio in transmission of movement from shaft 3| to shaft 35suffers simultaneously an increment and a diminution, but as thesevariations are not equal owing to the excentricity 2 between shafts 3|and 35, a differential change in the transmission gear ratio follows.

The principle upon which the device described works is the same as inthe differential corrector shown in my Patent No. 2,021,560. Thesubstantial difference between this latter and the device hereindescribed consists in the use of two fiat friction discs instead of twoconic friction pulleys.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a device of the class described, the combination of areciprocating film-carrier for effecting the intermittent movement of afilm across the field of a lens, means comprising a rocker for producingand transmitting a reciprocating movement to said film-carrier, meansfor continuously forcing a contact between the reciprocatingfilm-carrier and the aforesaid rocker, said means comprising fixedhollow cylinders provided with pistons slidable therein, said pistonsbeing connected to said reciprocating film carrier and means forcontinuously feeding with compressed air the inner chamber of saidcylinders; the aforesaid pistons being arranged in order to force acontact between the reciprocating film-carrier and the rocker under thepressure of compressed air.

2. In a device of the class described, the combination of areciprocating film-carrier for effecting the intermittent movement of afilm across the field of a lens, means comprising a rocker for producingand transmitting a reciprocating movement to said film-carrier, meansfor continuously forcing a contact between the reciprocatingfilm-carrier and the aforesaid rocker, said means comprising fixedhollow cylinders provided with pistons slidable therein, pushing rodsfor connecting said pistons to the reciprocating fllmcarrier, and meansfor continuously feeding with compressed air the inner chamber of thecylinders.

3. In a device of the class described the combination oi a reciprocatingfilm-carrier for eifecting the intermittent movement 01' a film acrossthe field of a lens, fixed hollow cylinders,

reciprocating pistons slidable in said cylinders, said pistons beingconnected to said reciprocating film carrier and means for reciprocatingsaid pistons, said means comprising a device for continuously feedingwith compressed air the inner chamber of the aforesaid cylinders; thevelocities of the reciprocating pistons and their mass being sodetermined that the inertia reactions produced by them are always equalin value but opposite in direction to the inertia reactions produced bythe reciprocating film-carrier.

4. In a device of the class described, the combination of meanscomprising a reciprocating film-carrier for effecting the intermittentmovement of a film across the field of a lens, a rocker forreciprocating said film-carrier, fixed hollow cylinders, reciprocatingpistons slidable in said cylinders and arranged at both sides of thereciprocating film-carrier, means for continuously feeding withcompressed air the inner chamber of said cylinders, other rockers forreciprocating said pistons, pushing rods for connecting said pistons totheir respective rockers; and gearing for correlating the movement ofthe rocker which reciprocates the film-carrier and the movement of therocker which reciprocates the pistons in such a manner that the invertedreactions produced by the reciprocating film-carrier on its rocker andthe inverted reactions produced by the reciprocating pistons on theirrockers are equal in value but opposite in direction and consequentlybalanced.

PEDRO LIRA.

